Experimental Design.... PEASE HELP!!!!!!!

Question

3.   Did you just fart?----Mr. Vega wants to reduce the number of students with flatulence at LHS. He has created a new sauce that he thinks will reduce the production of body gas associated with eating the delicious lunch items offered on campus. He recruits 100 students with a history of gas problems. He has 50 of them (Group A) eat pizza with the new sauce. The other 50 (Group B) eat pizza with sauce that looks just like new sauce but is really just mixture of mayonnaise and food coloring. Both groups were told that they were getting the sauce that would reduce gas production. Two hours after eating the pizza, 30 students in group A reported having fewer gas problems and 8 students in group B reported having fewer gas problems.

A.  Which people are in the control group? _________________________________

B.  What is the independent variable? _________________________

C.  What is the dependent variable? ________________________________________________________________

D.  What should Mr. Vega’s conclusion be? ________________________________________________

E.  Why do you think 8 students in group B reported feeling better?_______________________________

 

4.   Does this make my muscles look big?

Ms. Heinz was told that a certain muscle cream was the newest and best thing on the market. It claims to double a person’s muscle power when used as part of a muscle-building workout. Interested in this product, she buys the special muscle cream and recruits Mr. Areida and Mr. Cunningham to help her with an experiment. Ms. Heinz develops a special weight-lifting program for Mr. Areida and Mr. Cunningham. She meets with them once every day for a period of 2 weeks and keeps track of the number of 100lb triceps curls done in 1 minute. Before each session Mr. Areida’s arms and back are lathered in the muscle cream, while Mr. Cunningham's arms and back are lathered with the regular lotion.

A.   Which person is the control group? ____________________________________________

Time	Mr. Areida	Mr. Cunningham
Initial Amount	18	5
After 1 Week	24	9
After 2 Weeks	33	17

B.  What is the independent variable? _______________________________________________

C.   What is the dependent variable? ________________________________________________

D.  What should Ms. Heinz’s conclusion be? ______________________________________________

Answer 1

Hi Aidan!

3a. When you design an experiment, the control group is the group that does not get the new treatment. So, since group A got the new special sauce and group B got mayonnaise and food coloring, group B is the control group.

3b. There are two main variables when you design an experiment- the independent and the dependent. The independent variable is what you change. In this experiment, which sauce the students received is the independent variable.

3c. Since the independent variable is which sauce they students received, the dependent variable is how much gas they report having. I remember these by thinking that the dependent variable depends on the independent variable

3d. Since many more students in group A reported less gas than in group B, he should conclude that the new sauce causes less gas in students.

3e. These students likely reported less gas because of the placebo effect. When people think they are receiving a new treatment, they are likely to report whatever it is they are supposed to feel (in this case, having less gas), and this is called the placebo effect.

4a. This is similar to the question above. The control group does not receive the treatment we are interested in- in this case the special muscle cream. Since Mr. Areida gets rubbed with the special lotion and Mr. Cunningham does not, Mr. Cunningham is in the control group.

B. There are two variables here we are interested in. She is investigating whether or not the special muscle cream affects muscle strength. Since she is changing who receives the muscle cream or not, that is the independent variable.

4c. From 4b, we can see that the muscle cream treatment is the independent variable. What is the effect she is looking for? She is looking to see if it affects muscle strength- so that is the dependent variable.

4d. Since Mr. Areida can do significantly more tricep curls than Mr. Cunningham, she should conclude that the muscle cream does in fact help.

I hope that this is helpful for you!